Magnetically actuated snap-action switch



June 10, 1969 E. GILLILAN I MAGNETICALLY ACTUATED SNAP-ACTION SWITCHFiled :July 31, 1967 INVENTOR.

EDWARD GILL-ALAN HIS AT'FQIQNEY United States Patent 3,449,700MAGNETICALLY ACTUATED SNAP-ACTION SWITCH Edward Gillilan, Highland Park,11]., assignor to Cherry Electrical Products Corporation, Highland Park,Ill., a corporation of Illinois Filed July 31, 1967, Ser. No. 657,157IntfCl. H01h /02, 9/00 US. Cl. 335-188 1 Claim ABSTRACT OF THEDISCLOSURE A magnet-carrying actuator for a snap-action switch whichincludes a magnet-carrying, flexible switch blade with the magnetspresenting like pole faces such that they tend to repulse each other,with the magnet on the actuator restricted to a predescribed path ofmovement, and with the switch blade being disconnected therefrom andfree to move in any direction resulting in a movement of the switchblade into circuit making positions between spaced apart fixedterminals.

The invention is best illustrated by the accompanying drawings in which:

FIG. 1 is a perspective view of the snap-action switch;

FIG. 2 is a side elevational view of the snap-action switch with theside cover removed and showing the parts thereof in their normalunactuated positions;

FIG. 3 is a side elevational view similar to FIG. 2 but showing theparts thereof in their actuated positions;

FIG. 4 is a perspective view of the switch case;

FIG. 5 is a perspective view of the magnet-carrying switch actuator; and

FIG. 6 is a side view of the magnet-carrying flexible switch blade.

Referring to FIG. 1 there is shown a switch 10 which includes a case 11and removable side cover 12. One end wall 13 of the case 11 is providedwith three parallelly extending slots 14, 15 and 16. Positioned in slots14 and 16 are a pair of elongated contact bearing terminals 17 and 18.Positioned in slot 15 is a blade terminal 19 which as seen in FIG. 6 hasa portion of its elongated length reduced as at 20 to provide a flexibleblade end 21. The free end of the flexible blade 21 which is positionedwithin the cavity 22 formed in the case 11 carries a magnet 23.

An actuator 24 is projected through an opening 25 formed in the top wall26 of the case 11. This actuator 24 .has an enlarged circular head 27which normally projects externally of the cavity 22 as seen in FIG. 1.Connected to the underside of the circular head 27 of the actuator 24 isa generally T-shaped body portion 28, the free ends of the cross arm ofwhich are adapted to be positioned in and slidably contained in slots 29formed in the confronting inner wall faces of the case 11 and cover 12.Carried by the bottom portion of the T-shaped body 28 of the actuator 24is a second magnet 30. Disposed between the magnet 30 and the bottomwall 31 of the casing 11 and contained in a' well 32 is a coil spring33which normally positions the actuator 24 such that the circular head 27is exposed through the opening 25 formed in the top wall 26 of thecasing 11.

The magnets 23 and 30 are so arranged that like pole faces thereof arepositioned in confronting relationship. In the present illustration thenorth pole faces of each of the magnets are positioned in confrontingrelationship.

When the actuator 24 is moved within the switch 10, the magnet 30carried thereby will pass in close proximity to the magnet 23 of theflexible blade 21. As like magnetic pole faces repel each other, thisdownward movement of magnet 30 will cause magnet 23 to move in alikewise downward direction so as to increase the contact pressurebetween the contact 34 carried by the blade 21 and the contact 35carried by the inner end of the terminal 18. After the actuator 24 hasbeen moved in its guided path formed by the slots 29 to a point wherethe magnet 30 carried thereby passes below the center line of the forcesof magnet23, the repulsion between the like pole faces of these magnetswill cause the switch blade 21 to move upwardly until the contact 34carried thereby engages contact 36 carried at the inner end of theterminal 17. The downward distance of travel of the actuator 24 islimited by the size of its head 27, which when it is depressed into theopening 25 its full depth, as seen in FIG. 3, it can no longer be moved.Thus the magnet 30 is in a position where its repulsion force maintainscontact pressure between contact 34 and terminal contact 36.

I have provided a switch Where the switch blade is movable Withoutphysical attachment or engagement by any moving member. The arrangementof the repulsing magnets in close proximity to each other with onemovable through a controlled path results in a switch where the firstcontact between the switch blade and a terminal is increased beforebreaking by the resulting movement of the switch blade. An added andextremely desirable feature is obtained through the use of the magneticforce fields in that the switch is teaseproof; that is, the movement ofthe blade 21 is a positive reaction to the magnetic fields around it andcannot be suspended between the fixed terminals. Without physicalcontact or deformation by a movable member the life span and electricalcapacity of the blade is increased.

While I have illustrated and described the preferred form ofconstruction for carrying my invention into effect, this is capable ofvariation and modification without departing from the spirit of theinvention. I, therefore, do not wish to be limited to the precisedetails of construction set forth, but desire to avail myself of suchvariations and modifications as come within the scope of the appendedclaim.

Having thus described my invention, what I claim as new and desire toprotect by Letters Patent is:

1. A magnetically-actuated switch, including a housing providingspaced-apart parallelly extending fixed terminals and an elongatedswitch blade having a free end extending therebetween and carrying acontact movable into and out of contact with either of the terminalswherein the improvement comprises:

(a) an actuator movable through the housing perpendicular to theterminals and in spaced close proximity to the free end of the switchblade,

(b) guide means provided by said actuator within said housing andcooperating therewith to guide said actuator in a fixed perpendicularpath to close proximity to the free end of the switch blade,

(0) guide slots of a predetermined length formed in confronting walls ofthe housing for receiving said guide means provided by said actuator forguiding and limiting the movement of said actuator through its pathrelative to the free end of the switch blade,

(d) a magnet carried by the actuator within the housing and movable withsaid actuator through its guided and limited path in close proximity tothe free end of the switch blade,

(e) said switch blade having a portion of its length reduced inthickness to provide a flexible free end which carries a second magnetbeyond the ends of said spaced terminals and in close proximity to the 4tween said magnets for returning said actuator and its magnet to theiroriginal position, and effecting the return movement of the switch bladeand its magnet to their original position.

path of travel of said actuator and the magnet carried thereby,

(f) each of said magnets being magnetized parallel to the long axis ofsaid switch blade and in an 0pposite direction of polarization so thatsaid magnets act to repulse one another such that when said actuator andits magnet is moved in one direction through its guided and limited paththe actuators magnet will FOREIGN PATENTS repulse said second magnet sothat said free end of 1,432,447 2/1966 Fran said switch blade is causedto'move in an opposite direction to the direction of movement of saidactu- 15 BERNARD GILHEANY, Prlmary Examine"- ator lts m g a H. BROOME,Assistant Examiner.

(g) a coil spnng 1n axial alignment with said actuator for yieldablyresisting movement thereof through the U CL X,R housing in onedirection, and having an expansion 335.. 2()6 force greater than themagnetic repulsing force beo 5 References Cited UNITED STATES PATENTS2,624,809 1/1953 Sinclaire.

3,273,091 9/1966 Wales. 10

